The present invention relates generally to the field of centrifugal sorting devices and, in particular, to an improved centrifugal sorting apparatus especially adapted for use in conjunction with the sifting of materials which have a tendency to agglutinate, clump, or otherwise clog the sifting apparatus.
Centrifugal-type sorting or sifting units find great utility in numerous fields, including the chemical, food, dairy product, pharmaceutical and plastic industries. Such devices are often used to sort or sift both dry powder and granular materials, both to achieve a uniformity of sifted particle size ("fines") and to eliminate unwanted materials of a larger size ("overs") from the desired product. As the materials sought to be sifted are normally of a relatively small diameter, the screening material used to separate such material from the undesirable elements is relatively fragile and is subject to clogging.
In particular, numerous materials, such as epoxy paint pigments, demonstrate a tendency to agglutinate or collect together by virtue of static charges on the particles. The resulting clumps of material affix themselves to the sifting screen or mesh, and significantly lessen the efficiency and throughput of the sifting process. Other products, by virtue of their particle shape or other characteristics, similarly can clog the screen. The use of vanes, paddles and the like to assist in agitation of the mass to be sifted is often of little value, and sometimes serves to aggrevate the problem, as the increased agitation applied to the particles can increase the level of static charge thereon.